As a pressure sensor which detects a pressure by making use of a deformation of a diaphragm accompanying pressurization, a pressure sensor which detects the deformation of a diaphragm accompanying pressurization as a strain by forming (attaching or the like) a strain gauge over the diaphragm is well known.
Such a strain gauge changes an electric resistance of itself even by a minimal deformation. Generally a method of measuring a differential voltage proportional to a pressure as an output by using four strain gauges as one set and constituting a bridge circuit is used well and a temperature characteristic of the strain gauges themselves can be compensated by constituting the bridge circuit. For example, even though strain gauges themselves have the temperature characteristic, the output of a strain sensor does not vary when the deformations of the four strain gauges caused by temperature variation are equal to each other.
Further, when the pressure of a measurement object is low and corrosion resistance is not required, a pressure sensor is used which is configured by forming a silicon diaphragm as a pressure receiving part by partially thinning a silicon substrate and forming strain gauges over the silicon diaphragm by impurity diffusion. A pressure sensor of such a configuration has the advantages that sensitivity is high and strain gauges can be formed as an integral structure over the silicon diaphragm and other advantages.
Such a pressure sensor however is not suitable when the pressure of the measurement object is high or when corrosion resistance is required and a pressure sensor configured by attaching strain gauges or attaching a strain sensor including strain gauges to a metal diaphragm is used frequently.
In Patent Literature 1, disclosed is a pressure sensor which is a micromachining type device for detecting a pressure value and includes two constituent components. More specifically, a first constituent component has a first diaphragm including a first material and a second constituent component including a second material has a first region and a second region. Further, the first region is thinner than the second region and the first diaphragm and at least a part of the first region are stiffly bonded to each other. Then in order to improve a type of a pressure sensor in which the first material has a thermal expansion coefficient larger than the second material, the first diaphragm including the first material is configured to transfer a horizontal inflation to the first region of the second constituent component with regard to temperature and the horizontal inflation is transferred through a first bonding material arranged between the first diaphragm and at least the part of the first region.